1. Field of the Invention
The present invention relates to an image display apparatus.
2. Description of the Related Art
Heretofore, in an image display apparatus, e.g., an organic EL display apparatus including a pixel formed by using an organic light emitting diode (OLED), a field-effect thin film transistor or capacitor is used in order to drive the organic light emitting diode.
For example, in a top emission type organic EL display apparatus, since the light of the organic light emitting diode on an element substrate is emitted from the side opposite to the element substrate side, the light is hardly blocked by a circuit layer disposed between the organic light emitting diode and the element substrate. Therefore, in the top emission type organic EL display apparatus, the circuit layer such as thin film transistors and the like can be disposed just below the light emitting region of the organic light emitting diode, and it is said there is an advantage that a wide light emitting region can be ensured.
In the above-described top emission type organic EL display apparatus, for example, in plan view, the thin film transistor is arranged at the center of the inside of the light emitting region of the organic light emitting diode, and the capacitor is arranged in the inside of the light emitting region and in the vicinity of the longer side of the light emitting region (Japanese Unexamined Patent Application Publication No. 7-111341).
According to the above-described known technology, the thin film transistor is arranged at the center of the inside of the light emitting region. However, the surface of the thin film transistor is in a complicated uneven shape as compared with the surface of the capacitor. Consequently, the film thickness of an organic layer constituting the light emitting region becomes nonuniform on the thin film transistor under the influence of the unevenness of the thin film transistor. Furthermore, since the organic layer has a small thickness, there is a problem in that the coverage by the organic layer may become incomplete and, thereby, the productivity of image display apparatus may be decreased.
In addition to the above related art, Japanese Unexamined Patent Application Publication No. 2004-191627 discloses an organic light-emitting display device comprising an organic light emitting element, a thin film transistor for driving the organic light emitting element, and a capacitor connected to the thin film transistor. In the organic light-emitting display device, the thin film transistor is arranged outside the organic light emitting element in plan view and the capacitor is arranged inside and outside the organic light emitting element in plan view.
Japanese Unexamined Patent Application Publication No. 2004-119219 discloses an active matrix type organic EL display comprising an organic EL element, a driving transistor, and a capacitor. In the active matrix type organic EL display, the driving transistor is arranged inside the organic EL element in plan view and the capacitor is arranged inside and outside the organic EL element in plan view.
Japanese Unexamined Patent Application Publication No. 2004-126121 discloses an organic EL display device comprising an organic EL element and a switch circuit having a low-temperature poly-silicon transistor for driving, a low-temperature poly-silicon transistor for addressing, and a capacitor. In the organic EL display device, the transistors and the capacitor which constitute the switch circuit are arranged inside the organic EL element in plan view.
Japanese Unexamined Patent Application Publication No. 2003-208109 discloses an active matrix type display device comprising an organic LED element, a transistor for driving the organic LED element, and a capacitor. In the active matrix type display device, the transistor is arranged inside the organic LED element in plan view and the capacitor is arranged inside and outside the organic LED element in plan view.